To measure the serum succinyl trialanine p-nitroanilide hydrolytic activity as new index of liver function in workers exposed to organic solvents, this study conducted 114 workers in department of shoe-making of shoes factories. The results obtained from this study were as follows: 1. The mean values of serum GOT, GPT, gamma GT in whole workers were 22+/-12.32, 20+/-9.65, 28+/-21.35IU/l, respectively and the mean value of serum STN hydrolytic activity was 0.08 0.05. 2. The serum STN hydrolytic activity was significantly higher for male(p<0.05) and there was no difference among the groups of age. 3. There was no difference in the groups by working hours but significant difference in persons who worked over 3 years or were exposed to toluene over 100ppm(p<0.05). 4. The correlation of the exposed dose of toluene and serum GOT, GPT, gamma GT and serum STN hydrolytic activity were statistically significant(r=0.027-0.518). 5. The exposed dose of toluene was most explainable variable and statistically significant among the factors affecting serum STN hydrolytic activity(p<0.05).